Age-related production of spotted souslik (Spermophilus suslicus) interferon.

Interferon production by virus stimulated spotted souslik tissue explants in vitro depends on the age of the tissue donor and on the kind of tissue. The interferon titers in foetal liver were 1/120-1/370 and foetal lungs 1/21-1/500 of these observed in autologous organs of adult sousliks after infection in vitro with Newcastle disease virus, Radom strain (NDV-R). After birth interferon response in vivo develops with the age. Nine-day-old suckling sousliks were not able to respond with interferon production to lipopolysaccharide (LPS), but serum interferon levels after intraperitoneal (i.p.) injection of polyinosinic polycytidylic acid complex (poly I. poly C) complexed with diethyl-amino-ethyl-dextran (DEAE-dextran) or after injection of NDV-R were nearly similar to those in adult animals. In tissue however, levels of interferon were always lower than in adults. Young 4-5-week-old sousliks responded to induction with NDV-R and poly I. poly C with DEAE-dextran and tilorone hydrochloride as adults and produced interferon in serum and different organs, however, after induction with LPS serum interferon level did not reach the values observed in serum of adult sousliks.